Introduction: Hereditary factor XI (FXI) deficiency is a rare coagulation disorder that may result in excessive bleeding requiring intervention to restore haemostasis.
Aim: The aim of this review was to report the current knowledge of the worldwide incidence and prevalence of FXI deficiency.
Methods: A targeted PubMed search using terms related to FXI deficiency was conducted to identify studies published from April 2002 through April 2022. A manual search supplemented the electronic search. Studies were eligible for data abstraction if they reported population-based incidence proportions/rates or prevalence proportions for FXI deficiency.
Results: The electronic and manual searches returned 253 publications. After applying exclusion criteria, seven publications were included in the analysis, including a global report from the World Federation of Haemophilia (WFH). Six publications provided information on the prevalence of FXI deficiency that included 74 countries and regions. The estimated prevalence of FXI in the WFH report ranged from 0/100,000 in several countries to 55.85/100,000 individuals in the United Kingdom. Prevalence estimates in the PubMed findings ranged from .1 to 246.2/1,000,000 inhabitants with varying methods of case identification and time periods of analysis. One study estimated the incidence of FXI deficiency in Yecla, Spain at 2% of blood donors and .09% of hospital inpatients/outpatients with activated partial thromboplastin time (aPTT) tests.
Conclusion: FXI deficiency is rare across the world, but additional steps could be taken to improve incidence and prevalence estimation, for example, development of a consistent FXI deficiency definition and incorporating genetic testing into a clinical routine to better identify and characterise cases.
Keywords: blood coagulation disorders; coagulation factor XI; epidemiology; haemophilia C; rare diseases.
© 2022 The Authors. Haemophilia published by John Wiley & Sons Ltd.